In the related art, there is a known high-frequency treatment tool with which biological tissue such as a mucous membrane or the like is treated by applying electricity in the form of a high-frequency current (for example, see Patent Literature 1).
This high-frequency treatment tool has a structure in which an electrode is disposed by being inserted into a sliding hole at the distal end of a flexible sheath having electrically insulating properties so that the electrode can be moved forward and backward in the axial direction, and with which a liquid that has been fed through the flexible sheath can be dispensed from the distal end of the flexible sheath via a liquid-feeding opening portion that communicates with the sliding hole.
With this high-frequency treatment tool, in the case in which bleeding occurs during high-frequency treatment performed by applying electricity to the electrode, washing can be performed by using a liquid, such as physiological saline or the like, dispensed from the distal end of the flexible sheath without having to replace the high-frequency treatment tool, and thus, it is possible to quickly and reliably perform hemostatic treatment for bleeding occurring during an operation. In addition, with this high-frequency treatment tool, because a large-diameter portion provided in the distal end of the electrode is disposed so as to close the liquid-feeding opening portion, the liquid can be released straight ahead by moving the electrode forward to dispose the large-diameter portion away from the liquid-feeding opening portion so that the flow of the liquid is not greatly affected by the large-diameter portion.